Towards the scale‐up of electrolysis with diamond anodes: effect of stacking on the electrochemical oxidation of 2,4 D

Abstract

BACKGROUND In recent years, the application of electrochemical wastewater treatment processes has proven to be very efficient in the removal of recalcitrant organic compounds. However, the scale‐up of the boron‐doped diamond (BDD) anode system for industrial applications has not been sufficiently evaluated. This study assesses the effect of increasing the number of compartments in the same electrochemical module (DiaCell® 1001) on the treatment of synthetic wastewater with pesticide 2,4‐D and chlorides. This commercial module can be considered to be a stack of cells, in which the number of single cells varies from 2–10 and the anode areas range from 140–700 cm−2. RESULTS The results of the study demonstrate that an increase in the number of cells and a decrease in the resulting current density at the same current intensity caused an increase in the removal and mineralisation rates. Complete mineralisation was attained in all configurations tested. The production of hazardous species, such as chlorates and perchlorates, are also affected by the number of stacked cells, which causes them to be positioned lower in the stack due to the large number of cells. CONCLUSIONS No distinct differences in electrochemical efficiency are observed among the different configurations tested. However, a distinct improvement in the energy efficiency (g kWh−1) with an increase in the number of stacked cells is observed due to the reduced stack potential caused by applying the same current intensity to the stack with the higher number of cells. © 2015 Society of Chemical Industry

Electroreductive Remediation of Halogenated Environmental Pollutants

“…For example, different cell configurations were tested for the oxidation of synthetic wastewater containing 2,4-D at boron-doped diamond anodes; energy efficiency improved with an increase in the number of stacked cells. 130 A recent study demonstrated that stacking 10 detachable electrolytic cells in a fashion similar to a single large flow-through cell results in a much higher efficiency for removal of a pollutant than a single batch reactor. 131 A similar continuous multicell reactor with a volume of 8.4 L was successfully used to treat effluents from a textile plant.…”

Novel integrated electrodialysis/electro-oxidation process for the efficient degradation of 2,4-dichlorophenoxyacetic acid

“…The research efforts devoted to the development of environmental applications of electrochemical technologies has notably increased within the last decades Feng et al, 2016). For the particular case of pesticide removal, many studies have been conducted in the recent years, looking for operation conditions or combination of processes that helps to attain high degradation efficiencies (Muff et al, 2009;Fontmorin et al, 2012;Kukurina et al, 2014;Souza et al, 2016) in the depletion of these hazardous species.…”

Scale-up of electrolytic and photoelectrolytic processes for water reclaiming: a preliminary study

“…Therefore, in the case of expensive anodic materials, such as borondoped diamond (BDD), the current density has to be as high as possible to minimize anodic surface but low enough to avoid undesired side reactions. In a first approach to scaling-up of CDEO, the effect of increasing the numbers of compartment in an electrochemical cell (DiaCell® 1001) has been studied by this research group for the treatment of wastewater polluted with herbicides (Souza et al 2015a). In that work, no differences were observed in the process efficiency when increasing the number of stacked cells.…”